The consequence of androgens and estrogens administered perinatally on hypothalamic luteinizing hormone-releasing hormone (LH-RH), serum LH and FSH, gonadal function and sexual behavior throughout the life-span of rodents will be investigated. A model for studying decline in reproductive capability based on the finding that a dosage-dependent relationship exists between perinatal androgen exposure and both longevity of normal ovulation and degree of receptivity is being evaluated. Hormonal and experiential factors will be introduced that could accelerate or retard decline in fertility. The relationship between perinatal hormones and development of sexual dimorphic characteristics are also being studied.